The invention relates to a solid solution-strengthened iron-nickel alloy having a high level of ductility and a low expansion coefficient in the low temperature range.
JP-A 60221193 discloses an iron-nickel alloy having the following composition (in weight %):
C <0.2%
S <0.006%
Ni 35-37%
Mn 1-3%
Si <0.1%
Ti 0.2-0.5%
P <0.02%
Fe Remainder, including production-related impurities.
This alloy can be used as a welding filler material for Ni 36 alloys.
DE-T 69125684 provides an alloy having the following composition (in weight %):
C 0.1-0.35%
S 0-0.05%
Cr 0-2%
Ni 31-45%
Mn 0-2.5%
Si 0-1%
Al 0-0.5%
Ti 0-0.75%
Nb 0.1-4%
P 0-0.05%
Fe Remainder and production-related impurities.
This describes a welding material that has a low expansion coefficient.
Due to their chemical composition, the alloys in this prior art cannot necessarily also be used in the low temperature range, for instance between room temperature and at least −165° C., so that appropriate modifications to the chemical composition are necessary.
If welding is performed using an iron alloy having 36% Ni (Ni36) using similar conventional, commercially-available filler materials, then the welded joint will not be as strong as the basic material, regardless of the welding process. In the overwhelming majority of uses in the temperature range above 0° C. this is not a major disadvantage because the mechanical properties play only a subordinate role. This is in contrast to the coefficient of thermal expansion, which as is known is particularly low with this iron-nickel alloy.